Script for scaning files

bhandu · 06-17-2007, 04:12 PM

I have developed a shell script which will scan two files and then put the similar records in a third file.The script is follows

rm $filename3
touch $filename3

exec < $filename1

while read line
do
exec <filename2
while read line1
do
if [ $line -eq $line1 ]
echo $line >> filename3
end if
done
done

But the above shell script is not working.
Could anyone help me out?

jschiwal · 06-17-2007, 06:25 PM

You seem to be fast and loose with the "$" character.

Code:

exec < $filename1

Are you trying to source a file here? The variable filename1 is undefined as well.
. $filename1

Code:

while read line1

This will read a line of input from stdin and place it in the variable line1
The read command should rarely be used in bash programs. It's better to pipe the output of one command into the input of another using the proper utilities to do the job.

Code:

exec <filename2

Are you trying to source a file named "./filename2"? Did you mean:
. $filename2
However filename2 would be undefined. Also the exec command will replace this shell with the program indicated by $filename2

Code:

do
if [ $line -eq $line1 ]
echo $line >> filename3
end if

If you wanted to output differing entries in two files, you could use the diff or comm commands instead.
The comm command works on sorted lists and prints out 3 columns. The first is items uniq to list1. The second is items uniq to list2, and the third is items common to both. You can suppress the output of the columns you don't want.

You may also be confusing the "exec" command with the eval command if you are trying to execute a line of code contained in a variable.

Tinkster · 06-17-2007, 07:10 PM

Dupe of
http://www.linuxquestions.org/questi...d.php?t=562272
and
http://www.linuxquestions.org/questi...d.php?t=562490

jtshaw · 06-17-2007, 07:54 PM

Please post your thread in only one forum. Posting a single thread in the most relevant forum will make it easier for members to help you and will keep the discussion in one place. This thread is being closed because it is a duplicate.